Lubricant having improved oxidation resistance



organic phosphorus acids.

United States Patent 3,256,183 LUBRICANT HAVING IMPROVED OXIDATION RESISTANCE Rudolph Greenwald, Cleveland, Ohio, assignor to The Luhrizol Corporation, Wicklifl'e, Ohio, a corporation ing improved resistance to deterioration under service conditions. The lubricant compositions are useful in in ternal combustion engines, especially engines of the diesel type.

The problem of deterioration of lubricating oils and formation of harmful deposits under service conditions has been the cause of much concern in providing satisfactory lubrication of internal combustion engines. The problem is especially acute in lubricating engines of the diesel type where the lubricant encounters temperatures above 700 F. and pressures above 1200 pounds per square inch. In recent years, it has been common practice to incorporate into a lubricating oil detergent additives which are capable of preventing the deposition of the products of oil degradation. Such additives include the metal salts of sulfonic acids, carboxylic acids and The basic metal salts, i.e., those in which the metal is present in stoichiometrically greater amounts than the organic acid radical, are especially effective for this purpose. Unfortunately, however, these metal detergents tend to promote oxidation of the oil. Thus, while lubricant compositions containing such additives are improved with respect to their detergent properties, they are usually also characterized by a marked susceptibility to oxidative degradation.

Accordingly it is an object of this invention to provide a means for reducing the oxidation tendencies of lubricant compositions having incorporated therein metal-containing detergent additives.

It is also an object of this invention to provide lubricant compositions adapted for use in internal combustion engines.

It is further an object of this invention to provide lubricant compositions adapted especially for use in diesel engines.

' hydrocarbons and chlorinated aliphatic hydrocarbons with an inorganic phosphorus reagent selected from the class consisting of phosphorus halides and phosphorus sulfides;

(C) From about 0.01 percent to about 0.5 percent by weight of anthranilic acid; and

(D) From about 0.01 percent to about 5 percent by Weight of an oil-soluble calcium phenate compound prepared by the process comprising the steps of reacting a mixture comprising 1 mole of an alkyl phenol and from about 1 to about 2 moles of a formaldehyde producing reagent in the presence of a catalyst at a temperature of from about C. to about 99 C. and thereafter reacting said mixture with a calcium reagent selected from the class consisting of calcium hydroxide and calcium oxide at a temperature of at least about 30 C.

To prepare the lubricating compositions of this inven- 3,256,183 Patented June 14, 1966 tion, the additives may simply be added to the oil at the appropriate concentrations. However, the ordinary practice is to prepare a lubricating additive concentrate by dissolving the additives in a limited amount of oil, optionally with other additives, and thereafter diluting the lubricating additive concentrate with additional oil to prepare the final oil compositions. The latter practice is preferred especially since it facilitates bulk storage and bulk shipment of the necessary ingredients in a form from -Which the lubricating compositions of this invention may be readily prepared. Therefore, contemplated for the indicated and other reasons as being Within the scope of this invention is a lubricating additive concentrate comprising at least about 20 percent by weight of mineral lubricating oil;

(A) From about 0.6 percent'to about 79 percent by weight of an oil-soluble calcium sulfonate;

(B) From about 0.6 percent to about 79 percent by Weight of an oil-soluble barium salt of an acidic composition selected from the class consisting of sulfonic acids and phosphorus acids derived from the reaction of a reactant selected from the class consisting of aliphatic hydrocarbons and chlorinated aliphatic hydrocarbons with an inorganic phosphorus reagent selected from the class consisting of phosphorus halides and phosphorus sulfides;

(C) From about 0.06 percent to about 4 percent by weight of anthranilic acid; and

(D) From about 0.06 percent to about 40 percent by weight of an oil-soluble calcium phenate compound prepared by the process comprising the steps of reacting a mixture comprising 1 mole of an alkyl phenol and from about 1 to about 2 moles of a formaldehyde producing reagent in the presence of a catalyst at a temperature of from about 10 C. toabout 99 C. and thereafter reacting said mixture with a calcium reagent selected from the class consisting of calcium hydroxide and calcium oxide at a temperature of at least about 30 C.

Thus, contemplated within the scope of this invention are compositions comprising at least about 20 percent by Weight of mineral lubricating oil;

(A) From about 0.1 percent to about 79 percent by weight of an oil-soluble calcium sulfonate;

(B) From about 0.1 percent to about 79 percent by weight of an oil-soluble barium salt of an acidic composition selected from the class consisting of sulfonic acids and phosphorus acids derived from the reaction of a reactant selected from the class consisting of aliphatic hydrocarbons and chlorinated aliphatic hydrocarbons with an inorganic phosphorus reagent selected from the class consisting of phosphorus halides and phosphorus sulfides;

(C) From about 0.01 percent to about 4 percent by weight of anthranilic acid; and

(D) From about 0.01 percent to about 40 percent by weight of an oil-soluble calcium phenate compound'prepared by the process comprising the steps of reacting a mixture comprising 1 mole of an alkyl phenol and from about 1 to about 2 moles of a formaldehyde producing reagent in the presence of a catalyst at a temperature of from about 10 C. to about 99 C. and thereafter reacting said mixture with a calcium reagent selected from the class consisting of calcium hydroxide and calcium oxide at a temperature of at least about 30 C.

The amount of the detergent additives to be used in. a lubricant composition of this invention will depend primarily upon the degree of detergency desired in the lubricant composition and the type of service to which the lubricant composition is to be subjected. For example, a lubricant for use in a gasoline engine of a passenger automobile may contain from 0.5% to 5% by weight of the detergent additives, Whereas a lubricant for use in a diesel engine may contain as mucst as 20% or more of the detergent additives. In other applications such as in two-cycle outboard motor type engines, a lubricant may contain only 0.2% or even less of thedetergent additives.

The anthranilic acid is used in the lubricant compositions of this invention to reduce the oxidation-promoting tendencies of the metal detergent additive. Hence, the amount of anthranilic acid to be used depends to a large extent upon the amount and the type of the detergent additive used. A small amount of a detergent additive will usually require a correspondingly small amount of anthranilic acid. In most instances, from 0.01% to 0.5%, more often in the neighborhood of 0.02%0.2%, by weight of anthranilic acid in a final lubricant will suflice to counteract the oxidation tendencies of a lubricant containing a detergent additive.

Anthranilic acid is not readily soluble in mineral oil and its solubilization may require a short period of heating accompanied by stirring. For the purposes of this invention it is preferable to add it to a mineral oil'which already contains the detergent additive. The anthranilic acid dissolves easily in such a medium and there are thus no solubility difficulties.

The sulfonic acids from which the detergent additives of this invention are derived may be either petroleum sulfonic acids (e.g., mahogany acids) or alkylaryl sulfonic acids prepared by the treatment of alkylated aromatic compounds with a sulfonating agent such as sulfur trioxide, chlorosulfonic acid, sulfuric acid or the like. The organic radical of the sulfonic acid should contain at least about 12 aliphatic carbon atoms in order to impart oil-solubility.

The organic phosphorus acids from which the detergent additives are derived are principally those prepared by the treatment of a polymer of a lower mono-olefin such as ethylene, propene, isobutene or l-butene with a phosphorizing agent such as phosphorus pentasulfide, phosphorus heptasulfide, phosphorus sesquisulfide, phosphorus trichloride, phosphorus trichloride and sulfur, elemental phosporus and a sulfur chloride, phosphorothiolic chloride, etc. They may also be prepared by chlorinating an olefin polymer and treating the chlorinated polymer with a phosphorizing agent. The phosphorized polymer may be hydrolyzed (effected by, e.g., water addition, water washing, or preferably, steam blowing at a temperature of from about 100 C. to about 260 C.) first before conversion to the metal salts. Interpolymers of the aboveillustrated lower mono-olefins, aromatic olefins or diolefins likewise are useful for preparing the organic phosphorus acids provided that at least about 95% by weight of the interpolymer is composed of the lower mono-olefin units. Examples of the olefin polymers include polyisobutenes, polypropenes, polyethylenes, copolymer of 90% of isobutene and 10% of styrene, copolymer of 98% of isobutene and 2% of chloroprene, copolymer of 99% of propene and 1% of piperylene, terpolymer of 98% of isobutene, 1% of butadiene and 1% of n-hexene, etc. Polymers of isobutene are most frequently used because polymers may vary within wide ranges such as, for ex.- ample, from 200 to 100,000 or even higher. Polymers of intermediate molecular Weights, i.e., 50010,000 are especially useful.

As noted above the phosphorus acids are prepared from a substantially aliphatic hydrocarbon, i.e., one which may contain only incidental proportions of aromaticity and only such substituents as do not materially affect the aliphatic character of the molecule.

The calcium sulfonates and the barium salts of the sulfonic acids and organic phosphorus acids may be neutral or basic salts obtained by treatment of the acid with at least a stoichiometric amount of an alkaline earth metal neutralizing agent such as the metal oxide, metal hydroxide, metal carbonate, metal alcoholate, metal phenate, etc. The term basic metal salts is used to designate the metal of their ready availability. The molecular weights of the V droxide.

salts of organic acids wherein the metal is present in a larger amount than is stoichiometrically equivalent to the organic acid radical. Examples of such metal salts include those prepared by the processes described in US. Patents 2,616,905, 2,723,234, 2,921,901, 2, 902,105, 2, 906,709, 2,902,448, 2,865,956, 2,861,272, 2,316,080, and 2,316,081.

The most commonly employed methods for preparing the basic metal salts involve heating a mixture of an acid with a stoichiometric excess of a barium or calcium neutralizing agent at a temperature above about 50 C. and filtering the reaction mass in a diluent such as mineral oil to obtain a fluid product. The use of a promoter in the neutralization step to aid the incorporation of a large excess amount of metal is likewise known. Examples of such promoter compounds include phenolic substances such as phenol naphthol, alkyl phenol, thiophenol, sulfurized phenol and condensation products of formaldehyde and a phenol; alcohols such as methanol, 2-propanol, octyl alcohol, Cellosolve, carbitol, ethylene gylcol, stearyl alcohol, icyclohexyl alcohol; amines such as aniline phenylenediamine, phenothiazine, phenyl ,8 naphthylamine, dodecyl amine, etc. A particularly eflicient method comprises mixing an acid with an excess of a neutralizing agent, a promoter compound and a small amount of water, and carbonating the mixture at an elevated temperature, e.g., 60150 C.

The calcium phenate compound, an oxidation and corrosion inhibitor, is prepared by the process comprising the steps of reacting a mixture comprising '1 mole of an alkyl phenol and about 1 to about 2 moles of a formaldehyde producing reagent in the presence of a catalyst at a temperature of from about 10 C. to about 99 C. and thereafter reacting said-mixture with about 1 mole of a calcium reagent selected from the class consisting of calcium hydroxide and calcium oxide at a temperature of at least about 30 C.

As indicated, the process for preparing the calcium phenate compound comprises two steps, viz, a catalyzed condensation of formaldehyde and the alkyl phenol followed by reaction of the condensation product with the 7 calcium compound to form the phenate. In the first step of the process, addition of the catalyst initiates an exothermic reaction which is further completed with the aid of external heat.

The second step of the process is carried out at a temperature of at least about 30 C. The upper temperature limit of this step may be any temperature less than the decomposition temperature of the calcium phenate composition, e.g., it may be as high as 300 C. The usual temperature range for this step is from about C. to about 175 C. The calcium reagent is usually added to the reaction mixture at a lower temperature, e.g., -90 C. Then to avoid excessive foaming, it is desirable to heat the reaction mixture slowly until a major proportion of the water present from condensation or addition is removed and to thereafter heat rapidly to the higher temperature to drive off trace amounts of water.

The catalyst used in the process for preparing the calcium phenate compound may be an inorganic metal hydroxide or other suitable catalyst. Such catalysts include ammonium hydroxide, amines, and the oxides or hydroxides of alkali or alkaline earth metals. Examples of the latter include lithium hydroxide, sodium hydroxide, barium oxide or hydroxide, and calcium oxide or hy- Because of the difficulty associated with removing the catalyst from the calcium phenate compound,

it is preferred to use calcium oxide or calcium hydroxide A as the catalyst. That is, the calcium oxide or calcium hydroxide catalyst is preferred in that it serves to initiate the condensation reaction and is also consumed in the final step of the process for preparing the desired calcium phe'nate compounds. The amount of catalyst used is within the range of from about 0.01 mole to about 0.06 mole per mole of alkyl phenol. Because of the indicated catalystconsumption, when calcium oxide or calcium hydroxide is used the amount of these catalysts may range from about 0.01 to about 0.1 mole or more.

The alkyl phenol used in preparing the calcium phenates of this invention may be substituted with one or more alkyl radicals. To impart oil solubility to the calcium phenate of this invention it is preferred to use alkyl phenols having at least one alkyl radical containing at least about 7 carbon atoms. Alkyl phenols having at least one alkyl radical containing up to 30 carbon atoms or more are likewise useful. It is preferred that the indictated alkyl radicals be substantially free from unsaturation, i.e., containing one double bond or two double bonds in the long chain alkyl radicals and preferably no double bonds. Examples of alkyl phenols useful in this respect include heptylphenol, octylphenol, nonylphenol, decylphenol, dodecylphenol, eicosylphenol, triacontylphenol, p-decyl-o-ethylphenol, and polyisobutene (200-500 molecular weight) substituted phenols.

The formaledhyde producing reagent is, as implied, any reagent which will produce formaldehyde under the conditions of the indicated process. The molar quantities indicated refer to the amount of formaldehyde produced. Preferred examples of the formaldehyde producing reagent are paraforrnaldehyde, trioxane, and aqueous solutions of formaldehyde, e.g., 37% aqueous-formaldehyde.

Specific examples of the calcium phenate compound include those prepared from: 1 mole of heptylphenol, 1 mole of paraformaldehyde (based onthe monomeric structure), and 1 mole of calcium hydroxide; 1 mole of icetylphenol, 1.4 moles of formaldehyde, and 1 mole of calcium oxide; and 1 mole of octylphenol, 2 moles of formaldehyde, and 1 mole of calcium hydroxide.

The present invention contemplates also the use of auxiliary corrosion and oxidation inhibitors in conjunction with the detergents, anthranilic acid, and the calcium phenate compound. A particularly important class of such inhibitors are the Group H metal salts of organic phosphorodithioic acids, especially the zinc and barium salts of dialkyl phosphorothioc and dialkaryl phosphorodithioic acids. Apart from serving as oxidation and corrosion inhibitors, these metal salts are effective extreme pressure additives and prevent valve train wear, viz,

Wear on the cam surfaces, the valve lifter faces, the valve tip, the rocker arm tips, etc. The intermediate acids used -in preparing these metal salts are preferably these in which the total number of carbon atoms in the twoalkyl radicals isat least about 7.6 per each phosphorus atom. Particularly useful are the phosphorodithioate inhibitors described in US. Patent 3,000,822. Especially useful is the zinc salt of the acid prepared by reactingone mole of phosphorus pentasulfide with four moles of an alcohol mixture consisting of '65 mole percent of i-butyl alcohol "and35 mole percent of primary pentyl alcohol.

Still another class of corrosion inhibitors includes the .sulfurized or phosphosulfurized hydrocarbons or fatty .di pentyl trisulfide, etc.

Other corrosion inhibitors are the metal salts of organic thiocarbamic acids such as zinc diheptylphenyl dithiocarbamate, zinc dipentyl dithiocarbarnate, cadmium cyclohexyl thiocarbamate, etc.

Yet another class of corrosion inhibitors consists of 'organic phosphites, especially diaryland dialkyl phosphites having the formula, (RO) P(O)H, wherein R is an aryl or an alkyl radical containing 4-30 carbon atoms. They may be prepared by the reaction of an alcohol or phenol or a mixture of alcohols or phenols with phosphorus trichloride. Examples of such phosphites include:

.dicyclohexyl phosphite, di(4-methyl-2-pentyl)phosphite,

propyl octyl phosphite, methylcyclohexylpentyl phosphite, diphenyl phosphite, etc. Other phosphites such as triphenyl phosphite, tributyl phosphite, and hexyl dicresyl phosphite are likewise contemplated.

While any of the indicated auxiliary corrosion inhibitors may be used, the particular combination of anthranilic acid, a calcium phenate compound, a zinc dialkyl phosphorodithioate, a barium detergent, and a calcium detergent has been found to produce lubricants which show unexpectedly high resistance to oxidation. Accordingly, such a combination is preferred for use in preparing the lubricants of this invention.

The auxiliary corrosion inhibitor may be used in the lubricant compositions of this invention at concentration-s within the range of from about 0.01% to about 5% by weight, more often within the range of fro-m about 1% to about 3% by weight. The range in lubricating additive concentrates would be from about 0.06% to about 40% by weight.

The use in the lubricant compositions of this invention of other types of additives such as antifoam agents, rustinhibitors, pour point and viscosity index improving agents, etc., is likewise contemplated.

The following examples illustrate more specifically the additives useful in the lubricant compositions of this invention. All parts are by weight unless otherwise indicated.

Example A.Neutral calcium detergent additive A mineral oil solution containing 50% by weight of a sodium pertoleum sulfonate (molecular weight 500) is heated at C. for 2'hours with a 20% stoichiometrically excessive amount of calcium chloride and 10% by weight of Water. The mixture is then dehydrated by heating to 15 0 C. and the inorganic chlorides removed by filtration. The filtrate is an oil solution of a neutral calcium petroleum sulfonate.

Example B..Basic calcium detergent additive A mixture of 520 parts of a mineral oil, 480 parts of a sodium petroleum sulfonate (molecular weight of 480) and 84 parts of water is heated at C. for 4 hours. The mixture is then heated with 88 parts of a 76% aqueous solution of calcium chloride and 72 parts of lime (90% purity) at 100 C. for 2 hours, dehydrated by heating to a water content of less than 0.5%, cooled to 50 C., mixed with parts of methyl alcohol and blown with carbon dioxide at 50 C. until substantially neutral. The mixture is then heated to C. to distill off methyl alcohol and water and the resulting oil solution of the basic calcium sullfonate filtered. The filtrate is found to have a sulfate ash of 16%.

Example C.-Baslc calcium detergent additive A mixture of 300 grams of mineral oil, 690 grams (0.5

mole) of neutral calciu m mahogany sulfonate, 75 grams of water and 29 grams of lime (90% purity) is heated at 100 C. for 2 hour-s and then to 150 C. during a period of 7 hours. The mixture is blown with carbon dioxide .at 150 C. until substantially neutral and filtered. The

filtrate is found to have a sulfate ash content of 8.2%. Example D.Basic calcium detergent additive A mixture of 500 parts of a mineral oil, 500 parts of a neutral sodium petroleum sulfonate (molecular weight of 500), 67 parts of calcium chloride and 76 parts of water is heated at 100 C. for 4 hours and then mixed with 25.5 parts of lime (90% purity) at 100 C. for 2 hours. The mixture is then dried to 150 C. over a period of 7.5 hours and filtered. The filtrate is found to have a sulfate ash content of 10%.

Example E.Basic barium detergent additive A mixture of 490 parts of a mineral oil, 110 parts of water, 61 parts of heptylphenol, 340 parts of neutral barium mahogany sulfonate and 227 parts of barium oxide is heated at 100 C. for 0.5 hour and then to 150 C. Carbon dioxide is then bubbled into the mixture until the mixture is substantially neutral. The mixture is filtered and the filtrate found to have a sulfate ash content of 25 Example F.Basic barium detergent additive To 900 parts of a chlorinated polyisobutene having a chlorine content of 4.3 and a molecular weight of 1,000 there is added 150 parts of phosphorus trichloride at 110 190 C. during a period of 15 hours. The mixture is heated at 200 C. for 2 hours, at 180190 C./660 mm. for 1.5 hours, and then blown with nitrogen at 170 C. for 2 hours. The residue is hydrolyzed with steam to form an acidic intermediate. A basic barium salt is prepared by adding 400 parts of the acidic intermediate to a mixture of 495 parts of a mineral oil, 100 parts of heptylphenol, 38 parts of water and 62 parts of barium oxide at 9095 C. during 1.5 hours. The mixture is heated at this temperature for 0.5 hour, mixed with 257 parts of barium oxide and carbonated at 130140 until it is substantially neutral. The resulting mixture is diluted with 280 parts of mineral oil and filtered. The filtrate is found to have a sulfate ash content of 25%.

Example G.Neutral barium detergent additive A polypropene having a molecular weight of 2,000 is mixed with by Weight of phosphorus pentasulfide at 190 C. for 6 hours. The resulting phosphosulfurized polypropene is hydrolyzed by treatment with steam at 160 C. to produce an acidic intermediate which is then converted to the neutral barium salt by treatment with a stoichiometric amount of barium hydroxide.

Example H .-Neutral barium detergent additive To 4,400 grams of a mineral oil solution containing 4.25 moles of sodium mahogany sulfonate there is added 680 grams of barium chloride dihydrate in 1500 ml. of water at 95 C. The mixture is heated at 80-90 C. for 1.5 hours, and the aqueous layer removed. The oil layer is washed With water-isopropanol-phosphoric acid mixture, then dried at 160 C./30mm. and filtered. The filtrate has a sulfate ash content of 10.7%.

Example I.-Basic barium detergent additive A mixture of 900 grams of a mineral oil solution con taining 0.41 mole of barium mahogany sulfonate, 46 grams of barium oxide, 145 grams of water and 64 grams of mineral oil is heated at 93 99 C. for 2 hours, thenheated to 150 C. in 7 hours, and filtered. The filtrate has a sulfate ash content of 15.6%.

Example ].Neutral calcium detergent additive To 6,500 grams of a mineral oil solution containing 6.53 moles of sodium mahogany sulfonate there is added at 95 C. 622. grams of calcium chloride dihydrate in 1,800 ml. of water. The mixture is heated at 95 -100 C. for 0.5 hour and allowed to settle at room temperature for 2 days. The aqueous layer is removed, and the oil layer is washed with water and then with a water isopropatrol-phosphoric acid mixture. The washed layer is dried and filtered. The filtrate has a sulfate ash content of 6.9%.

Example K.Basic barium detergent additive To a mixture of 1,000 parts of a chlorinated polyisobutene having a chlorine content of 4.3% and a molecular weight of 1000 and 110 parts of phosphorus trichloride, there is added portion-wise throughout a period of 0.5 hour 61 parts of heptylphenol at 210 F. The mixture is heated to 390 F. whereupon an additional 110 parts of phosphorus trichloride is added throughout a period of 6 hours. The mixture is heated at 390 F. for 0.5 hour, blown with nitrogen at 360 F./ 100 mm. for 2 hours, and then with steam at 300320 F. for 3 hours. To a mix ture of 270 parts of mineral oil, 18 parts of water and parts of barium oxide, there are added 143 parts of the above stearn hydrolyzed product and 38 parts of heptylphenol at 190-195 F., and then 125 parts of barium oxide at 200-230 F. The mixture is heated to 270- 280 F. and blown with carbon dioxide until substantially neutral. The mixture is heated to 270-280 F. and blown with carbon dioxide until substantially neutral. The residue is diluted with 120 parts of mineral oil, blown with nitrogen at 310 F. for 0.5 hour, and filtered. The filtrate has a sulfate ash content of Example L.--Basic barium detergent additive To a mixture of 6,245 grams (12.5 equivalents) of barium petroleum sulfonate, 1,460 grams (7.5 equivalents) of heptyl phenol and 2,100 grams of water in 8,045 grams of mineral oil there is added at 180 'F., 7,400 grams (96.5 equivalents) of barium oxide. The addition of barium oxide causes the temperature to rise to 290 F. and this temperature is maintained until all of the water has been distilled away. The mixture .then is blown with carbon dioxide until it is substantially neutral. 5,695 grams of mineral oil is added and the mixture filtered through a siliceous filter aid. The filtrate is diluted further with mineral oil to a barium content of 38.5% measured as sulfate ash.

Example M.Basic calcium detergent additive (Same as additive B except that sodium polydodecylbenzene sulfonate is used in the place of sodium mahogany sulfonate.)

Example N.Basic barium detergent additive A polyisobutene having a molecular weight of about 1,000 is phosphosulfurized by heating 944 parts of the polyisobutene with 85 parts of phosphorus pentasulfide at 260 C. for about 5 hours. The phosphosulfurized polymer is hydrolyzed by treatment with steam at 150-155 C. to produce an acid having a phosphorus content of 2.3% and a sulfur content of 2.7%. The hydrolyzed acid (300 parts) is added to a mixture of barium hydroxide monohydrate (311 parts) and mineral oil (485 parts) having a water content of less than 0.5% and at a temperature of 149-143 C. throughout a period of one hour. Heptylphenyl (153 parts) is added to the reaction mixture at 149 C. throughout a period of 0.5 hour. Carbon dioxide is bubbled parts/hour) through the reaction mixture at 154 C. for 4.3 hours. -More barium hydroxide monohydrate (181 parts) is added to the reaction mixture at 148 C. and then more carbon dioxide is bubbled (30 parts/hour) through the reaction mixture at 143l54 C(for 2.5 hours. Mineral oil (274 parts) is added to the reaction mixture and the whole is heated at 149 C. and blown with nitrogen gas (15 parts/ hour) for 2 hours, mixed with a filter aid and filtered. The filtrate is diluted further with mineral oil to a solution having a barium sulfate ash content of 38.5 a phosphorus content of 0.4%, and a sulfur content of 0.3%

Example 0.Calcium phenate compound oxidation and corrosion inhibitor Water parts) is added to a mixture of mineral diluent oil (2,250 parts) and heptylphenol (960 parts or 5 moles) at 27 C. To the reaction mixture at 41 C. there is added 231 parts (7 moles) of 91% pure paraformaldehyde throughout a period of 0.75 hour. Lime (catalyst, 6.6 parts or 0.16 mole) is added to the reaction mixture at 4143 C. and the whole is heated to C. over a period of 1.1 hours. More lime (200 parts or 4.8 moles) is added to the reaction mixture at'80-90" C. throughout a period of 0.75 hour. The reaction mixture is heated to 149 C. over a period of 5 hours, blown with nitrogen and heated at 149-454 C. for 7.2 hours, mixed with a filter aid, and filtered. The filtered product has a calcium content of 7.6% measured as sulfate ash.

Example P.Calcium phenate compound, oxidation and corrosion inhibitor The procedure of Example 0 is repeated except that 9 610 parts (7.5 moles) of 37% aqueous formaldehyde is used in lieu of the paraformaldehyde and water.

Example Q.Calcium phenate compound, oxidation and corrosion inhibitor The procedure of Example is repeated except that 1170 parts moles) of decylpheuol is used in lieu of the heptylphenol.

Example R.-Calcium phenate compound, corrosi n and oxidation inhibitor The procedure of Example 0 is repeated except that 2215 parts (5 moles) of a polyisobutene (350 molecular weight) substituted phenol is used in lieu of the heptylphenol.

Example S.--Calcium phenate compound, corrosion and oxidation inhibitor The procedure of Example 0 is repeated except that 1285 parts (5 moles) of ethyl substituted decylphenol is used in lieu of the heptylphenol.

:positions of this invention:

Lubricant I: Percent SAE 30 mineral oil 93.29 Basic calcium detergent of Example M 4.88 Basic barium detergent of Example L 1.13 Anthrauilic acid 0.08 Calcium phenate compound of Example 0 0.62

Lubricant II: Percent SAE 30 mineral oil 93.32

Basic calcium detergent of Example M 4.88 Basic barium detergent of Example L 1.13 Anthranilic acid 0.05 Calcium phenate compound of Example 0 0.62

Lubricant .III: Percent SAE 30 mineral oil 93.12 Basic calcium detergent of Example M 4.88 Basic barium detergent of Example L 1.13- Anthranilic acid 0.08 Calcium phenate compound of Example O 0.62 Zinc salt of the phosphorus acid prepared by reacting one mole of P S with 4 moles of an alcoholic mixture consisting of mole percent of i-butyl alcohol and 35% primary pentyl alcohol 0.17

Lubricant IV: Percent SAE 30 mineral oil 86.25

Basic calcium detergent of Example B 5.80 Basic barium detergent of Example E t 5.40 Anthranilic acid 0.05 Calcium phenate compound of Example 0 2.50,

Lubricant V: Percent SAE 20 mineral oil 87.95 Basic calcium detergent of Example B 4.56 Basic barium detergent of Example F 4.44

Anthranilic acid 0.05 Calcium phenate compound of Example 0 3.00

Lubricant VI: Percent SAE 10W-30 mineral oil 85.95

Basic calcium detergent of Example B 7.00 Basic barium detergent of Example K 4.00 Anthranilic acid 0.05 Calcium phenate compound of Example 0 3.00

Lubricant VII: Percent SAE 40 mineral oil 85.90 Basic calcium detergent of Example M 9.80 Basic barium detergent of Example L 2.28 Anthranilic acid 0.02 Calcium phenate compound of Example 0 2.00

' Lubricant VIII: Percent SAE 30 mineral oil 82.50 Basic calcium detergent of Example M 7.00 Basic barium detergent of Example L 6.00 Anthranilic acid 0.50 Calcium phenate compound of Example 0 2.50 Polyalkylsiloxane anti-foam agent 0.003

Polyalkylmethacrylate viscosity index improving' agent 1.50

Lubricant IX: Percent SAE 30 mineral oil 84.90 Basic calcium detergent of ExampleB 6.00 Basic barium detergent of Example E 4.00 Anthranilic acid 0.10 Calcium phenate compound of Example 0 3.00

' Polyalkyl acrylate viscosity index improving agent 2.00

Lubricant X: Percent SAE 30 mineral oil 87.90 Basic calcium detergent of Example D 4.00 Basic barium detergent of Example I 4.00 Anthranilic acid 0.10 Calcium phenate compound of Example 0 3.00

Zinc phosphorodithioate inhibitor of Example T 1.00

Lubricant XI: Percent SAE 30 mineral oil 93.19 Basic calcium detergent of Example M 4.88 Basic barium detergent of Example N 1.13 Anthranilic acid 0.08 Calcium phenate compound of Example 0 0.62 Zinc dihexyl phosphorodithioate 0.10

Lubricant XII: Percent SAE 30 mineral oil 90.49 Basic calcium detergent of Example C 5.31 'Basic barium detergent of Example F 2.41 Anthranilic acid 0.07 Calcium phenate compound of Example 0 0.72 Zinc isopropyl hexyl phosphorodithioate 1.00

Lubricant XIII: Percent SAE 30 mineral oil 88.10 Neutral calcium detergent of Example A 4.10 Neutral barium detergent of Example G 3.20 Anthranilic acid 0.10 Calcium phenate compound of Example 0 2.50 The zinc salt described in Lubricant III 2.00

Lubricant XIV: Percent SAE 30 mineral oil 93.29 Basic calcium detergent of Example M 4.88 Basic barium detergent of Example N 1.13 Anthranilic acid 0.08 Calcium phenate compound of Example 0 0.62

The above lubricants are of course merely illustrative of the scope of .the invention includes the use of all the detergent additives and inhibitors previously illustrated as well as many others within the broad definition of the combination of the invention.

The oxidation resistance of the lubricants of this invention is shown by the results of the air oxidation test summarized in Table I. The test consists of bubbling -air at a rate of 1 cubic foot per hour into 300 grams of a viscosity occurs. The results are expressed in terms of percent of viscosity increase. It will be readily appreciated that asmaller increase in viscosity indicates a greater resistance to oxidative degradation of the lubricant.

The air oxidation test results summarized in Table I illustrates the effectiveness of the calcium phenate compound of Example as compared to another calcium phenate. The superiority of calcium phenate compound is especially important in the lubricating compounds of this invention which contains zinc dialkyl phosphorodithioates, e.g., compare Lubricant III with Lubricant 111*. The importance resides primarily in the superior valve train wear properties which the indicated phosphorodithioates impart to the lubricants of this invention. It is noted that lubricants similar to the lubricants of this invention, but not containing any calcium phenate compound, have poor oxidation stability.

TABLE I AIR OXIDATION TEST RESULTS Test Sample Percent Viscosity Increase at End of 1 Test Period of No. Description 120 144 166 192 216 240 hours hours hours hours hours hours 1 Lubricant I 7 9 9 12 60 2 Lubricant I* 7 0 ll 63 147 3 Lubricant II 5 6 9 v 10 11 29 4 Lubricant 11*..- 4' 8 8 15 136 139 5 Lubricant III 9 10 11 I4 17 19 6 Lubricant 111*" 10 36 143 348 620 Lubricant 1*: Same as Lubricant I except that the calcium phenate compound of Example 0 is replaced with 0.62% of acalcium phenate prepared by heating a mixture of 315 parts or mineral oil, 125 parts of heptylphenol, and 26.4 parts of lime at 41-42 C. for 10 minutes; adding 5.8 parts of aqueous ammonium hydroxide and 29.3 parts of paral'ormaldcliyde to the mixture at 4049 0.; heating the mixture at 69-82 C. for 1 hour, to 149 C. in 5 hours, and at 149-152 O. for 1 hour; mixing the reaction mixture with a filtering aid; and filtering the whole. The product has a sulfate content of 6.2%.

Lubricant II": Same as Lubricant II except that the calcium plienate compound of Example 0 is replaced with 0.62% of the same calcium phenate as indicated for Lubricant 1*.

Lubricant III": Same as Lubricant III except that the calcium pheuatc compound of Example 0 is replaced with 0.62% of the same calcium phenate as indicated for Lubricant 1*.

combination in the same lubricant, most usually are sulfonates, i.e., a combination of a calcium sulfonate and a barium sulfonate. This particular combination is especially effective in the presence of anthranilic acid and the calcium phenate compound.

Examples of such lubricant compositions include mineral lubricating oils in which there are incorporated about 0.01%0.5% by weight of anthranilic acid, about 0.015% of the calcium phenate compound and detergent additive combinations such as: 1% of neutral calcium mahogany sulfonate and 5% of neutral barium mahogany sulfonate; 5% of neutral calcium didodecylbenzene sulfonate and 5% of neutral barium salt of the hydrolyzed reaction product of phosphorus pentasulfide with polyisobutene having an average molecular weight of 1000: 8% of a basic calcium salt of didodecylbenzene sulfonic acid prepared by carbonating at 60-80 C. a mineral oil solution of the acid with five chemical equivalents of calcium hydroxide in the presence of methyl alcohol as the promoter, and 8% of a neutral barium didodecylbenzene sulfonate; 10% of the calcium detergent ell of Example B and 2% of the barium detergent of Example L; 3% of the calcium detergent of Example D and 9% of the barium detergent of Example E.

The air oxidation test results summarized in Table II illustrate the unusual oxidation stability of lubricant compositions containing anthranilic acid, a calcium phenate compound, and such a mixture of barium and calcium de tergent additives.

The calcium and barium sulfonates used in the lubricant compositions indicated earlier as being especially preferred may be derived from either petroleum sulfonic acids or synthetic alkaryl sulfonic acids. Thus the barium sulfonate may be either barium mahogany or barium alkaryl sulfonate and the calcium sulfonate likewise may be either of these types. Further, the combination of calcium and barium sulfonates in one lubricant composition may include all possible combinations of calicum, barium, mahogany sulfionates and synthetic :alkaryl sulfonates.

TABLE II Percent Viscosity Increase at End of Test Period at Test Anthranilic Sample 1 Acid Ctr-Detergent Ba-Detergent 120 144 166 192 216 240 264 hours hours hours hours hours hours hours 0. 075 4.9% Additive 1.13% Additive 7 7 9 11 12 13 14 of Ex. M. of Ex. L. 0.075 6.1% Additive 58 174 347 858 of Ex L. 0.075 6.1% Additive 10 10 11 14 15 63 194 of Ex. M. 0.075 4.9% Additive 1.13% Additive 7 7 10 11 12 13 of Ex. M. oi Ex. N. 0.075 6.1% Additive 10 115 260 544 1, 270

of Ex. N. 0. 05 4.9% Additive 1.13% Additive 5 6 9 10 11 29 of Ex. M. of Ex. L. 7 0.05 6.1% Additive 143 260 of Ex. L. p 8 0.05 6.1% Additive 7 8 12 25 101 218 of Ex. M. 9 0. 05 4.9% Additive 1.13% Additive 6 7 9 10 12 23 of Ex. M. of Ex. N. 10 0. 05 6.1% Additive 82 141 259 of Ex. N.

1 All of the test samples contain 0.62% of the calcium phenate compound of Example 0.

It has been found also that lubricant compositions containing a mixture of barium and calcium detergent additives in weight proportions within the range of from about 5:1 to about 1:5 respectively, are especially susceptible to the oxidation-retarding eiiects of anthranilic acid and the calcium phenate compound. Ordinarily lubricant compositions contain from about 0.1% to about 10% of each of the calcium and barium detergent additives. These calcium and barium detergent additives, when used in 13 of a reactant selected from the class consisting of aliphatic hydrocarbons and chlorinated aliphatic hydrocarbons with an inorganic phosphorus reagent selected from the class consisting of phosphorus halides and phosphorus sulfides;

(C) from about 0.01 percent to about 4 percent by weight of anthranilic acid; and

(D) from about 0.01 percent to about 40 percent by weight of a calcium phenate compound prepared by the process comprising the steps of reacting a mixture comprising 1 mole of an alkyl phenol and from about 1 to about 2 moles of the formaldehyde producing reagent in the presence of a catalyst at a temperature of from about C. to about 99 C. and thereafter reacting said mixture with a calcium reagent selected from the class consisting of calcium hydroxide and calcium oxide at a temperature of at least about 30 C.

2. The composition of claim 1 characterized further in that it contains from about 0.1 percent to about 40 percent of a Group II metal salt of a dialkyl or dialkaryl phosphorodithioic acid.

3. A lubricating additive concentrate consisting essentially of at least about percent by weight of mineral lubricating oil;

(A) from about 0.6 percent to about 79 percent by weight of an oil-soluble calcium sulfonate;

(B) from about 0.6 percent to about 79 percent by weight of an oil-soluble barium salt of an acidic composition selected from the class consisting of sulfonic acids and phosphorus acids derived from the reaction of a reactant selected from the class consisting of aliphatic hydrocarbons and chlorinated aliphatic hydrocarbons with an inorganic phosphorus reagent selected from the class consisting of phosphorus halides and phosphorus sulfides;

(C) from about 0.06 percent to about 4 percent by weight of anthranilic acid; and

(D) from about 0.06 percent to about 40 percent by weight of a calcium phenate compound prepared by the process comprising the steps of reacting a mixture comprising 1 mole of an alkyl phenol and from about 1 to about 2 moles of a formaldehyde producing reagent in the presence of a catalyst at a temperature of from about 10 C. to about 99 C. and thereafter reacting said mixture with a calcium reagent selected from the class consisting of calcium hydroxide and calcium oxide at a temperature of at least about 30 C.

4. A lubricating composition comprising a major proportion of mineral lubricating oil;

(A) from about 0.1 percent to about 10 percent by Weight of an oil-soluble calcium sulfonate;

(B) from about 0.1 percent to about 10 percent by weight of an oil-soluble barium salt of an acidic composition selected from the class consisting of sulfonic acids and phosphorus acids derived from the reaction of a reactant selected from the class consisting of aliphatic hydrocarbons and chlorinated aliphatic hydrocarbons with an inorganic phosphorus reagent selected from the class consisting of phosphorus halides and phosphorus sulfides;

(C) from about 0.01 percent to about 0.5 percent by weight of anthranilic acid; and

(D) from about 0.01 percent to about 5 percent by weight of'a calcium phenate compound prepared by the process comprising the steps of reacting a mixture comprising 1 mole of an alkyl phenol and from about 1 to about 2 moles of a formaldehyde producing A reagent in the presence of a catalyst at a temperature of from about 10 C. to about 99 C. and thereafter reacting said mixture with a calcium reagent selected from the class consisting of calcium hydroxide and 14 calcium oxide at a temperature of at least about 30 C.

5. A lubricating composition comprising a major proportion of mineral lubricating oil:

(A) from about 0.5 percent to about 10 percent by weight of an oil-soluble, carbonated, basic calcium sulfonate;

(B) from about 0.5 percent to about 10 percent by weight of an oil-soluble, carbonated, basic barium sulfonate;

(C) from about 0.01 percent to about 0.15 percent by weight of anthranilic acid; and

(D) from about 0.1 percent to about 2 percent by weight of an oil-soluble calcium phenate compound prepared by the process comprising the steps of reacting a mixture comprising about 1 mole of heptylphenol and about 1.5 moles of formaldehyde in the presence of about 0.03 mole of calcium hydroxide at a temperature of from about 10 C. to about 99 C. and thereafter reacting about 1 mole of said calcium hydroxide with said mixture at a temperature of from about 30 C. to about 175 C.

6. The lubricating composition of claim 5 characterized further in that it contains from about 0.05 percent to about 2 percent by weight of a zinc dialkyl phosph-orodithioate derived from a phosphorodithioic acid prepared by the reaction of 1 mole of phosphorus pentasulfide and 4 moles of an alcohol mixture consisting of 65 mole percent of isobutyl alcohol and 35 mole percent of primary pentyl alcohol.

7. A lubricating composition comprising a major proportion of mineral lubricating oil:

(A) from about 0.5 percent to about 10 percent by weight of an oil-soluble, carbonated, basic calcium sulfonate;

(B) from about 0.5 percent to about 10 percent by Weight of an oil-soluble, carbonated, basic barium salt of a phosphorus acid derived from the reaction of about 11 parts of a polyis-obutene polymer having a molecular weight of about 1000 and about 1 part of phosphorus pentasulfide;

(C) from about 0.01 percent to about 0.15 percent by weight of anthranilic acid; and

(D) from about 0.1 percent to about 2 percent by weight of an oil-soluble calcium phenate compound prepared by the process comprising the steps of heating a mixture comprising about 1 mole of heptylphenol and about 1.5 moles of formaldehyde in the presence of about 0.03 mole of calcium hydroxide at a temperature of from about 10 C. to about 99 C. and thereafter reacting about 1 mole of said calcium hydroxide with said mixture at a temperature of from about 30 C. to about C.

8. The lubricating composition of claim 7 characterized further in that it contains from about 0.05 percent to about 2 percent by weight of a zinc dialkyl phosphorodithioate derived from a phosphorodithioic acid prepared by the reaction of 1 mole of phosphorus pentasulfide and 4 moles of an alcohol mixture consisting of 65 mole percent of isobutyl alcohol and 35 mole percent of primary pentyl alcohol.

References Cited by the Examiner UNITED STATES PATENTS 2,629,693 2/1953 Barton et a1. 252427 X 2,723,234 11/ 1955 Assefi et al 25232.7 2,846,466 8/1958 Crosby et a1. 25233 X 2,849,398 8/1958 Moody et al 25232.7 3,000,822 9/ 1961 Higgins et al 25232.7 3,146,201 8/1964 Butler 25251.5 X

DANIEL E. WYMAN, Primary Examiner.

P. P. GARVIN, Assistant Examiner. 

1. A COMPOUND CONSISTING ESSENTIALLY OF AT LEAST ABOUT 20 PERCENT OF MINERAL LUBRICATING OIL; (A) FROM ABOUT 0.1 PERCENT TO ABOUT 79 PERCENT BY WEIGHT OF AN OIL-SOLUBLE CALCIUM SULFONATE; (B) FROM ABOUT 0.1 PERCENT TO ABOUT 79 PERCENT BY WEIGHT OF AN OIL-SOLUBLE BARIUM SALT OF AN ACIDIC COMPOSITION SELECTED FROM THE CLASS CONSISTING OF SULFONIC ACIDS AND PHOSPHORUS ACIDS DERIVED FROM THE REACTION OF A REACTANT SELECTED FROM THE CLASS CONSISTING OF ALIPHATIC HYDROCARBONS AND CHLORINATED ALIPHATIC HYDROCARBONS WITH AN INORGANIC PHOSPHORUS REAGENT SELECTED FROM THE CLASS CONSISTING OF PHOSPHORUS HALIDES AND PHOSPHORUS SULFIDES; (C) FROM ABOUT 0.01 PERCENT TO ABOUT 4 PERCENT BY WEIGHT OF ANTHRANILIC ACID; AND (D) FROM ABOUT 0.01 PERCENT TO ABOUT 40 PERCENT BY WEIGHT OF A CALCIUM PHENATE COMPOUND PREPARED BY THE PROCESS COMPRISING THE STEPS OF REACTING A MIXTURE COMPIRSING 1 MOLE OF ANALKYL PHENOL AND FROM ABOUT 1 TO ABOUT 2 MOLES OF THE FORMALDEHYDE PRODUCING REAGENT IN THE PRESENCE OF A CATALYST AT A TEMPERATURE OF FROM ABOUT 10*C. TO ABOUT 99*C. AND THEREAFTER REACTING SAID MIXTURE WITH A CALCIUM REAGENT SELECTED FROM THE CLASS CONSISTING OF CALCIUM HYDROXIDE AND CALCIUM OXIDE AT A TEMPERATURE OF AT LEAST ABOUT 30*C. 